NXP USA Inc. PCA9531D,118

Description
The PCA9531 is an 8-bit I2C-bus and SMBus I/O expander optimized for dimming LEDs in 256 discrete steps for Red/Green/Blue (RGB) color mixing and back light applications. It contains an internal oscillator with two user programmable blink rates and duty cycles coupled to the output PWM. The LED brightness is controlled by setting the blink rate high enough (> 100 Hz) that the blinking cannot be seen and then using the duty cycle to vary the amount of time the LED is on and thus the average current through the LED.

Features
Eight LED drivers (on, off, flashing at a programmable rate)
Two selectable, fully programmable blink rates (frequency and duty cycle) between 0.59 Hz and 152 Hz (1.69 second and 6.58 milliseconds)
256 brightness steps
Input/outputs not used as LED drivers can be used as regular GPIOs
Internal oscillator requires no external components
RC-bus interface logic compatible with SMBus
Internal power-on reset

Applications
RGB color mixing
Back light applications
General Purpose parallel Input/Output (GPIO) expansion